The overall goal of the proposed research is to gain knowledge about mechanisms and evolution of signal pattern recognition. The research exploits the advantages of acoustic communication in frogs as a model system for exploring: (1) combinations of physical properties of signals that convey biologically significant information; (2) the operating principles by which nervous systems processes and extract such information; and (3) patterns of evolutionary change in signal pattern recognition. Because frogs do not require acoustic experience to produce or to recognize signals, this system can yield knowledge bearing on analogous problems in the recognition and discrimination of speech sounds by infants. That is, all languages draw from a common set of phonetic segments, and infants with little linguistic experience can discriminate among phonetic segments that do not even occur in the language that they will ultimately learn. This research thus addresses questions about inborn mechanisms of pattern recognition that make possible the development of normal speech, which, in turn, is important for human mental health. The proposed research will use playbacks of computer-synthesized signals that simulate male communication sounds; females respond to these sounds with positive phonotaxis and discriminate subtle differences in one or more properties. The research addresses interactions of discrimination criteria based on the frequency content of the signal and differences in fine-scale temporal properties. These interactions will be quantified in two closely related species; these results will then be used to select tests to be conducted with seven other species that are more or less closely related. These data, in conjunction with an independently derived estimate of the phylogenetic relationships of all nine species, will be used to assess how pattern recognition might have evolved. Mechanistic and environmental factors that could explain evolutionary trends will also be identified. Ultimately, this research will be important for framing testable hypotheses about sensory mechanisms underlying pattern recognition and for guiding the execution of such studies.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
1R01DC005760-01
Application #
6506477
Study Section
Special Emphasis Panel (ZRG1-BBBP-1 (01))
Program Officer
Luethke, Lynn E
Project Start
2002-07-01
Project End
2007-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
1
Fiscal Year
2002
Total Cost
$229,243
Indirect Cost
Name
University of Missouri-Columbia
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
112205955
City
Columbia
State
MO
Country
United States
Zip Code
65211
Gerhardt, H C; Humfeld, Sarah C (2013) Pre-existing sensory biases in the spectral domain in frogs: empirical results and methodological considerations. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 199:151-7
Tucker, Mitch A; Gerhardt, H C (2012) Parallel changes in mate-attracting calls and female preferences in autotriploid tree frogs. Proc Biol Sci 279:1583-7
Klymus, K E; Humfeld, S C; Marshall, V T et al. (2010) Molecular patterns of differentiation in canyon treefrogs (Hyla arenicolor): evidence for introgressive hybridization with the Arizona treefrog (H. wrightorum) and correlations with advertisement call differences. J Evol Biol 23:1425-35
Marshall, Vincent T; Gerhardt, H Carl (2010) A precedence effect underlies preferences for calls with leading pulses in the grey treefrog, Hyla versicolor. Anim Behav 80:139-145
Gordon, Noah M; Gerhardt, H Carl (2009) Hormonal modulation of phonotaxis and advertisement-call preferences in the gray treefrog (Hyla versicolor). Horm Behav 55:121-7
Gerhardt, H Carl; Brooks, Robert (2009) Experimental analysis of multivariate female choice in gray treefrogs (Hyla versicolor): evidence for directional and stabilizing selection. Evolution 63:2504-12
Gerhardt, H Carl (2008) Phonotactic selectivity in two cryptic species of gray treefrogs: effects of differences in pulse rate, carrier frequency and playback level. J Exp Biol 211:2609-16
Gerhardt, H Carl; Martinez-Rivera, Carlos C; Schwartz, Joshua J et al. (2007) Preferences based on spectral differences in acoustic signals in four species of treefrogs (Anura: Hylidae). J Exp Biol 210:2990-8
Jang, Y; Gerhardt, H C (2006) Divergence in the calling songs between sympatric and allopatric populations of the southern wood cricket Gryllus fultoni (Orthoptera: Gryllidae). J Evol Biol 19:459-72
Gerhardt, H Carl; Hobel, Gerlinde (2005) Mid-frequency suppression in the green treefrog (Hyla cinerea): mechanisms and implications for the evolution of acoustic communication. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 191:707-14

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